Like a warm toe approaching the edge of a cold lake, the new movie season is beginning slowly and cautiously, but not without promise. If the writers’ strike doesn’t end soon, 2008 might run out of product as fast as it begins, but for now the key word is optimism. After a bleak and baffling series of setbacks, Diane Keaton gets a career tweak in Mad Money, a mild comedy that penetrates its see-through cellophane wrap with a few good laughs and many performances that are even better.

Directed by Callie Khouri, who wrote the memorable Thelma & Louise, this fresh heist comedy about three women who decide to rob the Federal Reserve Bank is not exactly what I’d call revolutionary in either concept or execution, but I admit there were a few times when I actually laughed out loud. That’s pretty high praise indeed. When her husband, Don (Ted Danson), gets downsized, Kansas City housewife Bridget Cardigan finds that women her age are anathema to the workforce. The only job she can get is working as a cleaning lady at the government clearance bank where old currency from 1,000 other banks arrives daily to be sorted, inspected and destroyed. Scrubbing toilets and emptying the garbage is bad enough, but for a consumer queen with a black belt in shopping, an unemployed husband and more than $200,000 of debts, to be surrounded by so much unwanted money—well, it’s like Lucille Ball in the famous chocolate-factory assembly line episode of I Love Lucy.

What a waste. If the Federal Reserve Bank destroys one million dollars per day in dirty, worn-out bills, why shouldn’t somebody rescue a few, give or take a mil? So brainy Bridget comes up with a foolproof setup to relieve the economy of some of that green stuff before it turns brown. Of course, the master plan requires two co-workers turned partners-in-crime to carry it off like clockwork: Nina (Queen Latifah), a single mother who needs a higher living standard to get her two sons out of the slums and into college, and Jackie (Katie Holmes), a gum-chewing bimbo in a trailer home whose brain-dead husband, Bob (Adam Rothenberg), needs a new motorcycle. Nina actually shreds the money, and Jackie is in charge of the carts with the secret chain locks that transport the bills to the shredding machine. Bridget hides the rolled-up profits in the dustbins. When a sly security guard catches on, it looks like curtains, until Nina uses her bosomy charms to seduce him. Bob climbs eagerly on the bandwagon, and Don acts as their money manager. Now they’re a real gang, bonded in loyalty, convinced that money does indeed buy happiness and studying every aspect of the law to keep everything legal; some of the stuff you learn in Glenn Gers’ script is so valuable (no bank deposit up to $10,000 is ever reported to the IRS) that you might want to take notes.

Of course, after they all get rich for life, Bridget gets greedy. What she cites as “long-term security” Don sees as “long-term maximum security.” But these criminals are not ideologues. They aren’t fighting for animal rights, nuclear disarmament or the closing of the U.S. terrorist prison in Guantánamo. They just harvest old money nobody else wants anyway. Bridget even justifies it as improving the economy. I mean, think of it as recycling. When a nerdy federal bank examiner shows up at a backyard barbecue, they know the jig is up, and the plot takes a downward spiral toward disaster. But the fun gains momentum as they are forced to figure out ingenious ways to reverse their fortunes with record speed. Bridget suggests going into hiding and taking new identities. “Are you crazy?” yells Don. “What do we tell the kids?” Bridget, contemplatively: “Like they ever call us?”

Do they go to jail? Do they outsmart the government and get away with murder? No spoilers here. But do not underestimate the resourceful Ms. Keaton, who is as sharp and lovable and screwy as ever, even when the film is not. Along with jokes about everything from Martha Stewart to Victoria’s Secret, she keeps you laughing. The movie isn’t perfect. The characters exist situationally, never developing emotionally, but there’s more than one clever “twist” ending, and you will go away smiling. You also root for these zany crooks from start to finish. The point is that crime is contagious, and Mad Money proves it.